package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import lombok.NonNull;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.geo.Circle;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);

//        缓存击穿 互斥锁
//        Shop shop = queryWithMutex(id);
//        缓存击穿, 逻辑过期
//        Shop shop = cacheClient
//                .queryWithLogicalExpire(CACHE_SHOP_KEY,id,Shop.class,this::getById ,CACHE_SHOP_TTL,TimeUnit.MINUTES);
        //返回
        if (shop == null) {
            return Result.fail("获取店铺失败");
        }
        return Result.ok(shop);
    }


    /**
     * 缓存击穿
     * 互斥锁
     * @param id
     * @return
     */
    /*public Shop queryWithMutex(Long id){
        //1.根据id查询redis中存在
//        Map<Object, Object> entries = stringRedisTemplate.opsForHash().entries(CACHE_SHOP_KEY + id);
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);

//       2. 存在 就返回
        if (StrUtil.isNotBlank(shopJson)){
            return JSONUtil.toBean(shopJson, Shop.class);
        }

//        判断是否是空值
        if (shopJson != null){
            return null;
        }

        //3.实现缓存重建
//        3.1 获取互斥锁
        String lockKey = "lock:shop:"+id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
//        3.2 判断是否获取成功
            if (!isLock){
    //        3.3 失败,休眠一段时间重新获取缓存
                Thread.sleep(50);
                queryWithMutex(id);

            }
//        拿到锁进行 二次缓存判断
            String doubleTry = stringRedisTemplate.opsForValue().get(key);
            if (StrUtil.isNotBlank(doubleTry)){
                return JSONUtil.toBean(doubleTry, Shop.class);
            }
//        3.4 成功,进行数据重建

//      3.5  成功, 根据id去数据库中查询
            shop = getById(id);
//        4.数据库中不存在，返回404
            if (shop == null){
    //            将空值返回redis
                stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
                //店铺不存在
                return null;
            }
//        5.数据库中存在 ，先写入到redis中
            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {

//        6.释放互斥锁
        unlock(lockKey);
        }

//      7.  返回商铺信息
        return shop;
    }*/

    /**
     * 缓存穿透解决方案
     * 返回一个空值
     * @param id
     * @return
     */
   /* public Shop queryWithPassThrough(Long id){
        //1.根据id查询redis中存在
//        Map<Object, Object> entries = stringRedisTemplate.opsForHash().entries(CACHE_SHOP_KEY + id);
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);

//       2. 存在 就返回
        if (StrUtil.isNotBlank(shopJson)){
            return JSONUtil.toBean(shopJson, Shop.class);
        }

//        判断是否是空值
        if (shopJson != null){
            return null;
        }

//      3.  不存在 去数据库中查询
        Shop shop = getById(id);
//        4.数据库中不存在，返回404
        if (shop == null){
//            将空值返回redis
            stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL, TimeUnit.MINUTES);


            //店铺不存在
            return null;
        }
//        5.数据库中存在 ，先写入到redis中
        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
//      6.  返回商铺信息
        return shop;
    }*/


//    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

    /**
     * 逻辑过期解决缓存穿透
     *
     * @param
     * @return
     */
    /*public Shop queryWithLogicalExpire(Long id){
        //1.根据id查询redis中存在
//        Map<Object, Object> entries = stringRedisTemplate.opsForHash().entries(CACHE_SHOP_KEY + id);
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);

//       2. 不存在 就返回null
        if (StrUtil.isBlank(shopJson)){
            return null;
        }

        //3.命中 ,先把json反序列化为对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        //4. 判断是否过期
        if (expireTime.isAfter(LocalDateTime.now())){
        //5.1.未过期,返回店铺信息
            return shop;
        }
        //5.2.1.已过期

        //5.2.2 获取互斥锁

        String lockKey = LOCK_SHOP_KEY+id;
        boolean isLock = tryLock(lockKey);

        //5.2.3 判断互斥锁是否获取
        if (isLock){
        // TODO5.2.3.1 获取 开启独立线程实现缓存重建
            CACHE_REBUILD_EXECUTOR.submit(() ->{

                try {
                    //重建缓存
                    this.saveShopToRedis(id,20L);
                } catch (Exception e) {
                   throw new RuntimeException(e);
                }finally {

                //释放锁
                unlock(lockKey);
                }
            });

        }
//        //二次判断
//        String doubleTry = stringRedisTemplate.opsForValue().get(key);
//        if (doubleTry != null){
//            RedisData rs = JSONUtil.toBean(doubleTry, RedisData.class);
//            Shop shop1 = JSONUtil.toBean((JSONObject) rs.getData(), Shop.class);
//            LocalDateTime expireTime1 = rs.getExpireTime();
//            //4. 判断是否过期
//            if (expireTime1.isAfter(LocalDateTime.now())){
//                //5.1.未过期,返回店铺信息
//                return shop1;
//            }
//        }


        //5.2.3.2 返回过期的商铺信息,获取失败也返回 成功后也返回


//      6.  返回商铺信息
        return shop;
    }*/


   /* private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }*/

    /*private void unlock(String key){
        stringRedisTemplate.delete(key);
    }*/

   /* public void saveShopToRedis(Long id,Long expireSeconds){
        //1.查询店铺数据
        Shop shop = getById(id);

        //2.封装逻辑过期
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
//        3.写入redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
    }*/
    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("店铺可能不存在，店铺id不存在");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否根据坐标查询
        if (x == null || y == null) {
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
        }
        //2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        //3.查询redis、按照距离排序、分页 结果：shopId ，distance  georadius g1 116.378248 39.865275 10 km withdist
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo().radius(key,
                new Circle(x, y, 5000),
                RedisGeoCommands
                        .GeoRadiusCommandArgs.newGeoRadiusArgs()
                        .includeDistance()
                        .limit(end)
        );
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();

        //4.1截取from到end的部分
        if (list.size() <= from) {
//            没有下一页
            return Result.ok(Collections.emptyList());

        }

        //4.解析出id
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            //4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3.获取距离
            @NonNull Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        //5.根据id查询店铺
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD( id , " + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }


        //6. 返回

        return Result.ok(shops);
    }
}
